(Updates with comment from EPA)

WASHINGTON -(Dow Jones)- Governors of 18 U.S. states on Wednesday urged Congress to stop "harmful" Environmental Protection Agency regulation of greenhouse-gas emissions, saying the agency isn't equipped to deal with "the very real potential for economic harm."

The governors, led by Mississippi Gov. Haley Barbour, made their request in a letter to Senate Majority Leader Harry Reid (D., Nev.), House Speaker Nancy Pelosi (D., Calif.) and their Republican counterparts. The letter was also signed by Minnesota Gov. Tim Pawlenty, a Republican who has been cited as a possible contender in the 2012 presidential election.

"We feel compelled to guard against a regulatory approach that would increase the cost of electricity and gasoline prices, manufactured products, and ultimately harm the competitiveness of the U.S. economy," the governors wrote. "We strongly urge Congress to stop harmful EPA regulation of greenhouse-gas emissions that could damage those vital interests."

The Obama administration's EPA fired back that it "rejects the premise that addressing greenhouse gases threatens the economy," saying that other EPA actions "have led to innovations and the creation of new markets that can spur economic growth." The EPA "will continue to follow the law and the science, which overwhelmingly indicates climate change is a real and growing threat to the American people," spokesman Brendan Gilfillan said in a statement.

The governors' letter, signed mostly by Republicans, intensifies a battle with the Obama administration's EPA as it prepares to regulate greenhouse-gas emissions from vehicles and stationary sources such as power plants. The rules are due to be finalized by the EPA later this month. EPA Administrator Lisa Jackson has said the regulations for power plants, factories and oil refineries will be effective on a delayed basis, beginning in 2011, allowing companies extra time to plan ahead.

Coal, oil and manufacturing states have warned of the costs of complying, which could involve equipment purchases and other spending. In Congress, multiple measures are pending to hinder the EPA. One measure, from coal-state lawmakers including Sen. Jay Rockefeller (D., W.Va.) would suspend EPA regulations for two years. Another measure, led by oil-state Sen. Lisa Murkowski (R., Alaska) would overturn the EPA regulations.

"A simple delay of EPA action will do nothing to provide relief to Americans looking for jobs or businesses looking to make new investments in our states," the governors wrote in urging Congress to stop the EPA outright and to pass comprehensive energy legislation. "Furthermore, such delay of EPA action only creates more uncertainty in a difficult fiscal environment."

The letter emboldened Republicans already at odds with the EPA. Sen. Jim Inhofe (R, Okla.) said in a statement that the EPA should "stop this tax and the regulatory nightmare it will create, and work with Congress to pass an all-of-the-above energy plan that means more jobs, more energy, and more security for America."

The EPA's biggest champions in Congress have so far remained silent. A spokesman for Reid declined to comment. A spokesman for Pelosi didn't respond to a request for comment.

The EPA is acting after a 2007 Supreme Court decision found that carbon dioxide and other greenhouse gases are pollutants under the Clean Air Act and ordered the agency to determine whether to regulate the gas. The Obama administration's EPA last year found that greenhouse gases endanger the public, providing a basis for the rules it already has begun rolling out.

The agency is moving ahead as the Democratic-controlled U.S. Congress has struggled to advance Obama's energy agenda. The obstacles were highlighted on Tuesday, when Obama summoned 14 senators to the White House to discuss energy policy. No one could agree on an approach, except on the need to use energy more efficiently.

"We share the governors' opinion on one point: Administrator Jackson has said all along we would like to see comprehensive legislation to address this challenge and take advantage of the opportunity it poses," the EPA spokesman said.

The letter was also signed by West Virginia Gov. Joe Manchin, a Democrat, and Republicans including Alaska Gov. Sean Parnell and Louisiana Gov. Bobby Jindal. In addition to the 18 state governors, the governors of Guam and Puerto Rico also added their names.

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